Failed to execute cell. Could not send execute message to runtime: TypeError: Failed to fetch
Failed to fetch
TypeError: Failed to fetch
    at ra.program_ (https://ssl.gstatic.com/colaboratory-static/common/7dbb423deefb0652a5e445b39113beef/external_binary.js:8710:171)
    at ta (https://ssl.gstatic.com/colaboratory-static/common/7dbb423deefb0652a5e445b39113beef/external_binary.js:17:57)
    at ra.next_ (https://ssl.gstatic.com/colaboratory-static/common/7dbb423deefb0652a5e445b39113beef/external_binary.js:15:196)
    at saa.next (https://ssl.gstatic.com/colaboratory-static/common/7dbb423deefb0652a5e445b39113beef/external_binary.js:18:48)
    at https://ssl.gstatic.com/colaboratory-static/common/7dbb423deefb0652a5e445b39113beef/external_binary.js:18:463
    at new Promise (<anonymous>)
    at taa (https://ssl.gstatic.com/colaboratory-static/common/7dbb423deefb0652a5e445b39113beef/external_binary.js:18:356)
    at A (https://ssl.gstatic.com/colaboratory-static/common/7dbb423deefb0652a5e445b39113beef/external_binary.js:19:22)
    at g.fetch (https://ssl.gstatic.com/colaboratory-static/common/7dbb423deefb0652a5e445b39113beef/external_binary.js:8709:75)
    at ra.program_ (https://ssl.gstatic.com/colaboratory-static/common/7dbb423deefb0652a5e445b39113beef/external_binary.js:8711:50)
Copy error OK